There is a check box in the language module regarding detection of the preferred language of the browser.   I've done some experimenting with this and it doesn't seem to do anything.  
I set this in my browser, go to my dnn site.  I don't log in so my preferred language in the profile should not be in affect.  But even when I set to French, the language is still English.  English is the default for the site.

Could anyone help me understand how this is supposed to work or point me to a good source.
Thanks!

Hello dherman,

Have you found resolution to this issue or are you still having this issue and the question is still up on the table?

Please let us know and we're very sorry for our delayed response.

If you have any questions please let us know.

Thanks,

Ryan